The WRITEV procedure writes  characters  to  a  character-string
  variable  of  type  VARYING  OF CHAR or discriminated STRING, by
  converting the values of the parameters in the procedure call to
  textual representations.  The behavior of WRITEV is analogous to
  that of the WRITELN function; the character-string parameter  is
  analogous to a one-line file.

  Syntax:

     WRITEV( str, parameter-list
     [[,ERROR := error-recovery]] )

  The parameter 'str' cannot appear within the parameter-list;  if
  you  attempt to do this, unexpected results may occur.  An error
  occurs if WRITEV reaches the maximum  length  of  the  character
  string  before the values of all the parameters in the procedure
  call  have  been  written  into  the  string.    The   parameter
  'error-recovery'  indicates  the  action to be taken if an error
  occurs while the WRITEV procedure is executing.